It's not necessarily a bad time to trade. It's just merely a lower volume interval of the day. The highest volume intervals of the day are the first and last hours. The middle of the day, around lunch time, has the lowest volume per hour. Having said that, it's better to have a "buy dips & sell rallies" mentality near lunch time. Rallies and declines are more easily reversed because of the lighter volume propelling them.

# I know people who make money during that time period
# Our deadzone track record is actually quite profitable http://www.puretick.com/trkrecord.dz.html
# Wouldn't you like a lunch or exercise break? I dont know about you but I sit here from 7am to 4:30pm and would like to give my *** a rest. I come back refreshed and thinking more clearly.
# The volume is normally a lot lower in this period of the day. Pros do go to lunch too!

I think if you're there to trade you should trade. You don't know when a market is going to move, be it at lunch time or coffee time or surf for porn time. Follow your trading plan and don't listen to conventional wisdom, which is neither.